Mars’ ionopause characterization based on MAVEN and Mars Express observations

2020 ◽  
Author(s):  
Beatriz Sanchez-Cano ◽  
Clara Narvaez ◽  
Mark Lester ◽  
Michael Mendillo ◽  
Majd Mayyasi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Fields ◽  
Electron Density ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Thermal Pressure ◽  
Density Profiles ◽  
Electron Density Profiles

<p>The ionopause is a tangential discontinuity in the ionospheric thermal plasma density profile that marks the upper boundary of the ionosphere for unmagnetized planets. Since only Venus and Mars have no global “dipole” magnetic fields, ionopauses are unique to those planets. For Venus, the ionopause formation is well characterized because the thermal pressure of the ionosphere is usually larger than the solar wind dynamic pressure. For Mars, however, the maximum thermal pressure of the ionosphere is usually insufficient to balance the total pressure in the overlying magnetic pileup boundary. Therefore, the Martian ionopause is not always formed, and when it does, it is highly structured and is located at different altitudes. In this study, we characterise the Martian ionopause formation from the point of view of the electron density and electron temperature, as well as the thermal, magnetic and dynamic pressures. The objective is to investigate under which circumstances the Martian ionopause is formed, both over and far from crustal magnetic fields, and compare to the Venus’ case. We use several multi-plasma and magnetic field in-situ observations from the three deep dip campaigns of the MAVEN mission that occurred on the dayside of Mars (near subsolar point), as well as in-situ solar wind plasma observations from the Mars Express mission. We find that that 36% of the electron density profiles over strong crustal magnetic field regions had an ionopause event in contrast to the 54% of electron density profiles far from strong crustal magnetic field regions. We also find that the topside ionosphere is typically magnetized at mostly all altitudes. The ionopause, if formed, occurs where the total ionospheric pressure (magnetic+thermal) equals the upstream solar wind dynamic pressure.</p>

scholarly journals Cluster survey of the mid-altitude cusp: 1. size, location, and dynamics

2006 ◽  
Vol 24 (11) ◽  
pp. 3011-3026 ◽  
Author(s):  
F. Pitout ◽  
C. P. Escoubet ◽  
B. Klecker ◽  
H. Rème
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Time Delay ◽  
Interplanetary Magnetic Field ◽  
Statistical Study ◽  
Proper Time ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Summer Hemisphere ◽  
External Conditions

Abstract. We present a statistical study of four years of Cluster crossings of the mid-altitude cusp. In this first part of the study, we start by introducing the method we have used a) to define the cusp properties, b) to sort the interplanetary magnetic field (IMF) conditions or behaviors into classes, c) to determine the proper time delay between the solar wind monitors and Cluster. Out of the 920 passes that we have analyzed, only 261 fulfill our criteria and are considered as cusp crossings. We look at the size, location and dynamics of the mid-altitude cusp under various IMF orientations and solar wind conditions. For southward IMF, Bz rules the latitudinal dynamics, whereas By governs the zonal dynamics, confirming previous works. We show that when |By| is larger than |Bz|, the cusp widens and its location decorrelates from By. We interpret this feature in terms of component reconnection occurring under By-dominated IMF. For northward IMF, we demonstrate that the location of the cusp depends primarily upon the solar wind dynamic pressure and upon the Y-component of the IMF. Also, the multipoint capability of Cluster allows us to conclude that the cusp needs typically more than ~20 min to fully adjust its location and size in response to changes in external conditions, and its speed is correlated to variations in the amplitude of IMF-Bz. Indeed, the velocity in °ILAT/min of the cusp appears to be proportional to the variation in Bz in nT: Vcusp=0.024 ΔBz. Finally, we observe differences in the behavior of the cusp in the two hemispheres. Those differences suggest that the cusp moves and widens more freely in the summer hemisphere.

scholarly journals GPS phase scintillation at high latitudes during geomagnetic storms of 7–17 March 2012 – Part 1: The North American sector

2015 ◽  
Vol 33 (6) ◽  
pp. 637-656 ◽  
Author(s):  
P. Prikryl ◽  
R. Ghoddousi-Fard ◽  
E. G. Thomas ◽  
J. M. Ruohoniemi ◽  
S. G. Shepherd ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Geomagnetic Storms ◽  
Dynamic Pressure ◽  
Auroral Oval ◽  
Solar Wind Dynamic Pressure ◽  
Polar Cap ◽  
The North ◽  
Auroral Emission ◽  
Ground Magnetic

Abstract. The interval of geomagnetic storms of 7–17 March 2012 was selected at the Climate and Weather of the Sun-Earth System (CAWSES) II Workshop for group study of space weather effects during the ascending phase of solar cycle 24 (Tsurutani et al., 2014). The high-latitude ionospheric response to a series of storms is studied using arrays of GPS receivers, HF radars, ionosondes, riometers, magnetometers, and auroral imagers focusing on GPS phase scintillation. Four geomagnetic storms showed varied responses to solar wind conditions characterized by the interplanetary magnetic field (IMF) and solar wind dynamic pressure. As a function of magnetic latitude and magnetic local time, regions of enhanced scintillation are identified in the context of coupling processes between the solar wind and the magnetosphere–ionosphere system. Large southward IMF and high solar wind dynamic pressure resulted in the strongest scintillation in the nightside auroral oval. Scintillation occurrence was correlated with ground magnetic field perturbations and riometer absorption enhancements, and collocated with mapped auroral emission. During periods of southward IMF, scintillation was also collocated with ionospheric convection in the expanded dawn and dusk cells, with the antisunward convection in the polar cap and with a tongue of ionization fractured into patches. In contrast, large northward IMF combined with a strong solar wind dynamic pressure pulse was followed by scintillation caused by transpolar arcs in the polar cap.

scholarly journals Magnetic field variations in the Jovian magnetotail induced by solar wind dynamic pressure enhancements

2005 ◽  
Vol 110 (A11) ◽  
Author(s):  
Chihiro Tao ◽  
Ryuho Kataoka ◽  
Hiroshi Fukunishi ◽  
Yukihiro Takahashi ◽  
Takaaki Yokoyama
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Magnetic Field Variations

scholarly journals Azimuthally asymmetric ring current as a function of <i>D<sub>st</sub></i> and solar wind conditions

2004 ◽  
Vol 22 (8) ◽  
pp. 2989-2996 ◽  
Author(s):  
Y. P. Maltsev ◽  
A. A. Ostapenko
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Spatial Distribution ◽  
Interplanetary Magnetic Field ◽  
Ring Current ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Magnetic Data ◽  
Under Five ◽  
Solar Wind Parameters

Abstract. Based on magnetic data, spatial distribution of the westward ring current flowing at |z|<3 RE has been found under five levels of Dst, five levels of the interplanetary magnetic field (IMF) z component, and five levels of the solar wind dynamic pressure Psw. The maximum of the current is located near midnight at distances 5 to 7 RE. The magnitude of the nightside and dayside parts of the westward current at distances from 4 to 9 RE can be approximated as Inight=1.75-0.041 Dst, Inoon=0.22-0.013 Dst, where the current is in MA. The relation of the nightside current to the solar wind parameters can be expressed as Inight=1.45-0.20 Bs IMF + 0.32 Psw, where BsIMF is the IMF southward component. The dayside ring current poorly correlates with the solar wind parameters.

scholarly journals Magnetopause energy and mass transfer: results from a global MHD simulation

2006 ◽  
Vol 24 (12) ◽  
pp. 3467-3480 ◽  
Author(s):  
M. Palmroth ◽  
T. V. Laitinen ◽  
T. I. Pulkkinen
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Solar Wind ◽  
Energy Transfer ◽  
Dynamic Pressure ◽  
Solar Wind Dynamic Pressure ◽  
Closed Field ◽  
Dayside Magnetopause ◽  
Solar Wind Parameters ◽  
The Imf

Abstract. We use the global MHD model GUMICS-4 to investigate the energy and mass transfer through the magnetopause and towards the closed magnetic field as a response to the interplanetary magnetic field (IMF) clock angle θ=arctan (BY/BZ), IMF magnitude, and solar wind dynamic pressure. We find that the mass and energy transfer at the magnetopause are different both in spatial characteristics and in response to changes in the solar wind parameters. The energy transfer follows best the sin2 (θ/2) dependence, although there is more energy transfer after large energy input, and the reconnection line follows the IMF rotation with a delay. There is no clear clock angle dependence in the net mass transfer through the magnetopause, but the mass transfer through the dayside magnetopause and towards the closed field occurs preferably for northward IMF. The energy transfer occurs through areas at the magnetopause that are perpendicular to the subsolar reconnection line. In contrast, the mass transfer occurs consistently along the reconnection line, both through the magnetopause and towards the closed field. Both the energy and mass transfer are enhanced in response to increased solar wind dynamic pressure, while increasing the IMF magnitude does not affect the transfer quantities as much.

scholarly journals Understanding the origins of the heliosphere: integrating observations and measurements from Parker Solar Probe, Solar Orbiter, and other space- and ground-based observatories

2020 ◽  
Vol 642 ◽  
pp. A4 ◽  
Author(s):  
M. Velli ◽  
L. K. Harra ◽  
A. Vourlidas ◽  
N. Schwadron ◽  
O. Panasenco ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Fields ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Coronal Plasma ◽  
Solar Dynamics Observatory ◽  
Surface Magnetic Field ◽  
In Situ Observations

Context. The launch of Parker Solar Probe (PSP) in 2018, followed by Solar Orbiter (SO) in February 2020, has opened a new window in the exploration of solar magnetic activity and the origin of the heliosphere. These missions, together with other space observatories dedicated to solar observations, such as the Solar Dynamics Observatory, Hinode, IRIS, STEREO, and SOHO, with complementary in situ observations from WIND and ACE, and ground based multi-wavelength observations including the DKIST observatory that has just seen first light, promise to revolutionize our understanding of the solar atmosphere and of solar activity, from the generation and emergence of the Sun’s magnetic field to the creation of the solar wind and the acceleration of solar energetic particles. Aims. Here we describe the scientific objectives of the PSP and SO missions, and highlight the potential for discovery arising from synergistic observations. Here we put particular emphasis on how the combined remote sensing and in situ observations of SO, that bracket the outer coronal and inner heliospheric observations by PSP, may provide a reconstruction of the solar wind and magnetic field expansion from the Sun out to beyond the orbit of Mercury in the first phases of the mission. In the later, out-of-ecliptic portions of the SO mission, the solar surface magnetic field measurements from SO and the multi-point white-light observations from both PSP and SO will shed light on the dynamic, intermittent solar wind escaping from helmet streamers, pseudo-streamers, and the confined coronal plasma, and on solar energetic particle transport. Methods. Joint measurements during PSP–SO alignments, and magnetic connections along the same flux tube complemented by alignments with Earth, dual PSP–Earth, and SO-Earth, as well as with STEREO-A, SOHO, and BepiColumbo will allow a better understanding of the in situ evolution of solar-wind plasma flows and the full three-dimensional distribution of the solar wind from a purely observational point of view. Spectroscopic observations of the corona, and optical and radio observations, combined with direct in situ observations of the accelerating solar wind will provide a new foundation for understanding the fundamental physical processes leading to the energy transformations from solar photospheric flows and magnetic fields into the hot coronal plasma and magnetic fields and finally into the bulk kinetic energy of the solar wind and solar energetic particles. Results. We discuss the initial PSP observations, which already provide a compelling rationale for new measurement campaigns by SO, along with ground- and space-based assets within the synergistic context described above.

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